Datex-Ohmeda Aestiva 7900 SmartVent, Technical Reference Manual

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5 Troubleshooting
1006-0453-000 05/04 5-25
Bellows does not descend
during inspiration. 1. Normal
2. Leak in breathing system.
1. If the fresh gas flow is greater than tidal volume,
the bellows may not descend.
2. Check for leaks in drive gas circuit. Are twin tube
assemblies on the pneumatic engine lifted all the
way into the interface cuff?
Ventilator will not turn on
when remote on/off
switch is turned on and AC
LED is on 1. Machine interface harness
2. Remote on/off switch
3. Power supply board
1. Ensure cable is plugged in properly at switch and
CPU board (J5).
2. Replace switch
3. Replace power supply board
Erratic pressure waveform
Slow exhalation pressure
release
• Slight to moderate valve leakage
• O-Ring Seal, Housing to Main Manifold
• Alignment of seat and seal after assembly
• Loose mounting screws
• Exhalation valve assembly
1. Check operation of drive gas check valve.
2. Replace drive gas check valve.
3. Inspect and reassemble the exhalation valve
assembly; make sure to put it together correctly.
Mechanically delivered
volumes decrease
significantly immediately
following use of O
2
Flush.
Failure to cease Volume Compensation when
Flush is used.
• Flush switch
• Flush regulator out of adjustment
1. Go to “Display I/O signals” screen in Service
Mode (Section 5.2). Press and release flush button.
Look for proper switch action. Before replacing
switch, do step 2.
2. Check that output of flush regulator is within
specifications: 131 +0/-7 kPa (19 +0/-1 psi)
(Section 6.5 of Aestiva Machine Service Manual).
3. Check wire harness connections at switch and
SIB.
4. Replace CPU board.